The present disclosure relates to a printer that is capable of printing on a printing medium by using a thermal head, to a non-transitory computer-readable medium that stores a control program executable on the printer, and to a method that is executed by the printer.
A printer is known that includes a thermal head that has a plurality of heating elements. The printer causes the individual heating elements to generate heat by applying electric current to the individual heating elements. The printer thus performs printing by one of producing color on heat-sensitive paper and using hot melt ink to transfer a pattern to recording paper. In printing control for the thermal head, within a printing cycle in which one dot is printed, there must be, for example, a heating pulse time period for performing the printing and a non-heating time period for cooling the thermal head after the heating is finished.
When the printing starts, as well as when an isolated dot that stands alone is printed in the course of the printing, more than a little of the energy that is applied for generating heat may be used for initially heating the area around the heating element to its thermal capacity. Accordingly, the applied energy may be slightly insufficient. In order to compensate for the energy shortfall, the printing may be performed by adding an auxiliary pulse within the printing cycle, prior to the regular heating pulse, for example. In the case of a printer that uses heating elements that correspond to 128 dots, as an example of the thermal head, the printing operation may be performed by replacing data with every line. The auxiliary pulse may not be required for a heating element that is heated continuously since the heating element has been used for printing a dot for the preceding line. Conversely, in a case where a heating element that corresponds to a dot that precedes a print dot in a sub-scanning direction of the thermal head has not generated heat, and in a case where heating elements that correspond to dots that precedes and follows a print dot in a main scanning direction of the thermal head have not generated heat, the auxiliary pulse may be required. Therefore, within the printing cycle, the auxiliary pulse, the heating pulse, and the non-heating time period may be required.